Question 7
A child of mass 35 kg climbs a flight of stairs to a vertical height of 4 m. How much work does the child do? (g = 10 m s-2, mixed exercise question 3)
The right answer is the one marked above.
1400 J. work = m g h = 35 kg × 10 m s-2 × 4 m = 1400 J.
If the climb took one minute, the power would be 1400 J ÷ 60 s = 23.3 W — which is where the 23.3 in the options comes from. It is the answer to the next part of the question, and it is a power, not a work.